The present invention relates to a device for electromagnetic high energy pulse deformation of workpieces, in particular metal sheets, from an electrically conductive material, as well as to a method of electromagnetic high energy pulse deformation of workpieces.
Patent document DD 146 403 discloses a device for electromagnetic high energy pulse deformation, which is composed of a magnetic deformation coil as a deformation tool and “n” surge current generators. A device for electromagnetic high energy pulse deformation must be provided so that its application region is expanded with respect to the known devices without additional circuit and device-technical expenses. The device must be designed so that with a simple means, high storage energies can be obtained without reduction of the frequency of the discharge current.
In the known device it is achieved in that in the deformation tool of the device is composed of several partial coils, wherein each partial coil has only a few windings, in an extreme case only one winding, and is connected, potential-separately from the other partial coils, to a respective surge current generator which is ignitable simultaneously together with other surge current generators. The individual partial coils are assembled mechanically so that the magnetic fields of the individual partial coils are superimposed to provide a resulting magnetic field which acts on the workpiece. This is advantageous in that the delays of the partial streams of the individual surge current generators occurring by the different scattering times of the switching means are of secondary importance because of the sufficiently great current-delayed action of the inductivities of the partial coils. The discharge frequencies of the individual surge current circuits must be brought easily to superposition by the selection of the conductor lengths between the surge current generator and the corresponding partial coil of the deformation tool. With the use of a deformation tool assembled from a plurality of partial coils with low winding numbers and several surge current generators, it is possible to realize very high discharge frequencies and very high magnetic field intensities which act on the workpiece to be deformed.
The known device is composed substantially of a deformation tool and four surge current generators, wherein the deformation tool can be formed as a compression coil assembled of four oppositely electrically insulated single-winding partial coils. Each of the four partial coils of the deformation tool is connected to a respective one of the surge current generators, so that four separate surge current circuits are provided.
Instead of the compression coil, also a flat coil can be composed of four single-winding partial coils. It is also recommended to use an expansion coil or any other coil formed with subdivided windings.
With the known embodiment including flat coils, the partial coils shown in the patent document DD 146 403 with different diameters are arranged concentrically relative to one another so that an inwardly arranged coil has a different diameter than an outwardly arranged coil. As a result, all partial coils have different resistances and inductivities which can be compensated by additional features, such as winding numbers or differently long connection cables. However, the connection and the energy supply of such flat coils is extremely complicated and requires an increase in switching expense, wherein simultaneous deformation of the workpieces to be machined must be performed.